JPH0766160A - Abrasive method and apparatus for semiconductor substrate - Google Patents

Abstract

PURPOSE:To provide an abrasive method for semiconductor substrate in which uneven abrasion and hydroplane phenomenon are retarded and cleaning of abrasive cloth is facilitated and while prolonging the service life thereof. CONSTITUTION:A semiconductor substrate A is held on a substrate holder 14 with the surface thereof being exposed and while rotating the substrate about an axis 22 intersecting the substrate perpendicularly, a cylindrical rotary drum 26 applied with an abrasive cloth having microthrough holes is pressed against the surface of rotating substrate and rotated while moving back and forth. On the other hand abrasive liquid or cleaning liquid is introduced into the rotary drum and fed through the microthrough holes onto the surface of substrate thus abrading and cleaning the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and a polishing apparatus for a semiconductor substrate, and more particularly to a polishing method and a polishing apparatus having a good polishing property that can meet the demand for precision polishing of a semiconductor substrate. .

[0002]

2. Description of the Related Art Conventionally, on the surface of a semiconductor substrate, as shown in FIG. 4, a flat rotary platen 52 to which a polishing cloth 50 is attached is rotated around a shaft 54 while flowing a polishing liquid on the surface of the polishing cloth. It was polished by pressing the surface of the substrate A onto the polishing cloth. The substrate A is suction-held on the suction plate 56 by vacuum suction in the direction of the arrow.

[0003]

However, as the precision polishing of the substrate such as the interlayer flattening polishing of the integrated circuit substrate and the high precision flattening polishing of the SOI substrate is demanded, the conventional method is used in the conventional method. Since it is not possible to actually maintain a uniform surface contact between the polishing cloth and the polishing cloth, it is difficult to perform uniform precision polishing. Further, since a polishing liquid using a highly flat and hard polishing cloth is difficult to penetrate into the substrate surface, further difficult to uniformly and reliably supply the polishing liquid to the substrate surface,
There is a problem that uneven polishing occurs. Further, since a polishing cloth made of fine fibers or a polishing cloth made of a fine foam layer is used as the polishing material, clogging easily occurs in a short time due to polishing dust. Therefore, brushing or dressing with diamond pellets or the like is applied to the polishing cloth to remove polishing dust and clean the polishing cloth.
However, in reality, there is a problem that effective cleaning is difficult and the life of the polishing cloth is shortened. Further, the above-mentioned polishing cloth has a problem that the substrate easily floats during polishing (hydroplane phenomenon), and therefore, appropriate frictional resistance does not occur and the polishing rate decreases.

In view of the above problems, the present invention has been improved so that uneven polishing and hydroplane phenomenon hardly occur, cleaning of the polishing cloth is easy, and the life of the polishing cloth is extended, and a polishing method for a semiconductor substrate. Is to provide the ingredients.

[0005]

In order to achieve the above object, a method of polishing a semiconductor substrate according to the present invention holds a semiconductor substrate on a substrate holder so that the surface is exposed and is orthogonal to the substrate. While rotating the substrate around an axis, a cylindrical rotating drum wound with a polishing cloth having fine through holes is rotated forward and backward while pressing and contacting the surface of the rotating substrate, while rotating the drum. The polishing liquid or the cleaning liquid is introduced into the inside of the rotary drum, and the polishing liquid or the cleaning liquid is supplied to the substrate surface through the fine through holes provided in the rotary drum wall and the fine through holes of the polishing cloth, so that the semiconductor substrate is polished and cleaned. It is characterized by having done.

The means for holding the semiconductor substrate on the substrate holder is not particularly limited, but the substrate is held on the substrate holder by vacuum suction, for example. The polishing cloth used in the present invention may be a conventionally used one, for example, foamed polyurethane provided with fine through holes. Further, in order to supply the polishing liquid or the cleaning liquid to the surface of the substrate, it is preferable that, for example, pressurized air is supplied to the inside of the rotating drum so that the polishing liquid or the cleaning liquid flows out due to the pressure difference between the inside and the outside of the rotating drum. .
Further, for the convenience of cleaning the polishing cloth, the pressure inside the rotary drum may be reduced.

A semiconductor substrate polishing apparatus according to the present invention for carrying out the above-described method of the present invention holds a semiconductor substrate with its surface exposed and rotates the substrate about an axis orthogonal to the substrate. A combination of a holding table and a polishing tool for polishing the surface of a substrate on the rotating substrate holding table, wherein the substrate holding table includes a substrate suction plate that holds the substrate by vacuum suction.
The polishing tool includes a rotating mechanism that rotates the substrate suction plate around an axis orthogonal to the substrate, and the polishing tool includes a cylindrical rotating drum that is rotatable around a rotation axis along the longitudinal centerline, and a rotating shaft at both ends. A supporting arm for supporting the shaft and an advancing / retreating mechanism for advancing and retracting the rotating drum pressed and brought into contact with the substrate surface via the holding arm to rotate back and forth are provided, and a fine through hole is provided in the cylindrical wall of the rotating drum. Further, a water-permeable polishing cloth for polishing the surface of the substrate is attached to the outer peripheral surface of the cylindrical wall, and the rotating shaft of the rotary drum has a supply port for supplying a polishing liquid or a cleaning liquid from the outside and a polishing liquid from the supply port. Alternatively, it is characterized in that a means for introducing the cleaning liquid into the rotary drum is provided.

The water-permeable polishing cloth is, for example, a polishing cloth having a large number of fine through holes such as a polishing cloth made of a fine foam layer, or another kind of water-permeable and water-permeable polishing cloth. As the rotating mechanism of the substrate holder and the advancing / retreating mechanism of the rotating drum used in the present invention, known and commonly used mechanisms can be used. Further, in order to pressurize the inside of the rotating drum so that the polishing liquid or the cleaning liquid can easily flow out to the substrate surface, for example, pressurized air is supplied to the inside of the rotating drum, and the polishing liquid is applied by the pressure difference between the inside and outside of the rotating drum. Or, let the washing liquid flow out. Further, for the convenience of cleaning the polishing cloth, the pressure inside the rotary drum may be reduced.

[0009]

A method of polishing a semiconductor substrate according to claim 1 and claim 2.
In the polishing apparatus, the polishing liquid is uniformly supplied to the substrate surface from the entire surface of the polishing cloth through the fine through holes of the rotary drum and the fine through holes of the polishing cloth, so that polishing unevenness is eliminated. Also,
Since the polishing cloth is wound around the rotary drum, it does not come into surface contact with the surface of the rotating substrate but line contact or curved surface contact. Therefore, uniform contact is possible, and further, the hydroplane phenomenon does not occur. Therefore, sufficient frictional resistance can be obtained, and stable polishing can be performed at a high polishing rate.
Furthermore, since the cleaning liquid is supplied from the back surface of the polishing cloth to the front surface through the through holes of the rotary drum, the cleaning liquid sufficiently rinses away the polishing dust that has clogged the polishing cloth, thereby effectively cleaning. Therefore, the life of the polishing cloth is extended.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic perspective view for explaining the practice of the method of the present invention using a polishing tool and a substrate holder, and FIG.
3 is a schematic side sectional view of the polishing tool shown in FIG. 3 and FIG. 3 is a schematic side sectional view showing the essential parts of the polishing tool and the substrate holder shown in FIG. The method for polishing a semiconductor substrate according to the present invention is carried out by using a polishing apparatus 10 including a combination of a polishing tool 12 and a substrate holder 14 as shown in FIG. Substrate holder 1
As shown in FIG. 3, 4 is a disc-shaped suction plate support 16
And a porous suction plate 20 fitted in the cylindrical recess 18 of the suction plate support 16. The suction plate support 16 is
The rotation device (not shown) rotates together with the suction plate 20 around the rotation shaft 22 in the direction of arrow W. Furthermore, the rotary shaft 22
Has a through hole 24 along its center line, and the through hole 24 penetrates the suction plate support 16 and penetrates the suction plate 2.
It communicates with 0. The substrate A is placed on the suction plate 20, and the substrate A can be firmly held on the suction plate 20 by vacuum suction of the substrate A via the through holes 24 and the suction plate 20.

The polishing tool 12 is provided with a rotary drum 26 and a holding arm 28 for holding the rotary drum 26. The rotary drum 26 is pressed against and brought into contact with the substrate A on the rotating substrate holder 14 and the rotary drum 26 is held. It is used in such a way as to rotate 26 back and forth. The rotary drum 26 is
As shown in FIG. 2, the rotary shaft 3 is a cylindrical drum whose both end surfaces are closed and which extends along the longitudinal centerline thereof.
It is configured to freely rotate around 0. The rotary shaft 30 is pivotally supported by the holding arms 28 at both ends thereof. A flexible hose 36 (see FIG. 1) is connected to a supply port 32 provided at one end of the rotary shaft 30 to supply a polishing liquid or a cleaning liquid. Further, the supply port 32 is connected to a conduit (not shown) arranged in the rotary shaft 30, and the rotary drum 2 is connected through a plurality of downward nozzles provided in the conduit.
A polishing liquid or a cleaning liquid is supplied to the inner portion 34 of 6. The rotating drum 26 is forcibly given a rotational force from the outside by belt driving (not shown) or the like, and rotates as indicated by an arrow U.

The outer peripheral surface of the cylindrical wall of the rotary drum 26 is covered with a porous polishing cloth 38 that allows water to pass from the back surface to the front surface, for example, MH polishing cloth manufactured by Rodel Nitta Corporation. Further, the cylindrical wall of the rotary drum 26 is provided with a large number of through holes 40 having a small diameter in a uniform distribution. In the polishing apparatus 10, a commonly used means (not shown) for introducing compressed air is provided on the rotary drum 26 so that compressed air can be introduced to pressurize the inside 34 of the rotary drum 26. The polishing liquid or cleaning liquid of the rotating drum 26 is caused to flow to the surface of the substrate A through the through hole 40 of the cylindrical wall of the rotating drum 26 and the water-permeable polishing cloth 38 by the pressure difference generated inside and outside the rotating drum 26. There is.

A polishing method for a semiconductor substrate according to the present invention using the polishing apparatus 10 having the above structure will be described with reference to FIGS. The substrate A is attached to the suction plate 20 of the substrate holder 14.
It is placed on top and a vacuum suction device (not shown) is activated to suck in the direction of arrow V (see FIG. 3). As a result, the substrate A is firmly held on the suction plate 20. Then, a rotation device (not shown) is activated to move the substrate holder 14 to the rotation shaft 22.
Rotate around in the direction of arrow W at an appropriate number of rotations.

Next, the polishing tool 12 is prepared and the hose 36
The polishing liquid is introduced into the inside 34 of the rotary drum 26 via
While pressing the rotary drum 26 with compressed air, the rotary drum 26 is pressed and brought into contact with the substrate A and is moved back and forth in the direction of arrow X via the holding arm 28 as shown in FIG. The polishing liquid flows from the inside 34 of the rotary drum 26 to the rotary drum 26.
Bleed on the substrate A through the through hole 40 of the cylindrical wall and the polishing cloth 38. Further, by introducing the cleaning liquid into the through holes 40 of the rotating drum 26 and the porous holes of the polishing cloth 38 in the same manner as the polishing liquid, the scrubber cleaning and the cleaning of the polishing cloth for clogging can be continuously performed. it can.

[0015]

According to the method of polishing a semiconductor substrate of the first aspect of the present invention, while rotating the semiconductor substrate, the rotating drum wound with the polishing cloth is pushed back and forth while pressingly contacting the substrate surface, while the rotating drum is rotated. By introducing a polishing liquid or a cleaning liquid into the inside of the substrate and supplying these polishing liquids to the surface of the substrate through the fine through holes of the rotary drum, the polishing liquid is uniformly supplied onto the substrate, so that polishing unevenness is eliminated. Moreover, since the polishing cloth contacts the substrate surface not by a flat surface but by a curved surface, the hydroplane phenomenon does not occur. Therefore, sufficient frictional resistance can be obtained, and stable polishing can be performed at a high polishing rate. Furthermore, since the cleaning liquid is supplied from the back surface of the polishing cloth to the front surface through the through holes of the rotary drum, the cleaning liquid sufficiently rinses away the polishing dust that has clogged the polishing cloth, thereby effectively cleaning. Therefore, the life of the polishing cloth is extended. By applying the method of the present invention, it is possible to meet requirements for precision substrate polishing such as interlayer flattening polishing of an integrated circuit substrate and highly accurate flattening polishing of an SOI substrate.

According to the second aspect of the present invention, there is provided a combination of a substrate holder for rotating the substrate while holding the substrate by vacuum suction, and a polishing tool for polishing the surface of the substrate in cooperation with the substrate holder. The polishing tool includes a rotatable rotary drum having a water-permeable polishing cloth wound around the outer periphery thereof, and the polishing liquid or the cleaning liquid is applied to the substrate surface from the inside of the rotation drum through the through hole of the rotation drum wall and the water-permeable polishing cloth. With the configuration of the polishing apparatus that supplies the polishing liquid, the polishing liquid is uniformly supplied onto the substrate, so that polishing unevenness is eliminated. Moreover, since the polishing cloth contacts the surface of the substrate with a curved surface instead of a flat surface, the hydroplane phenomenon does not occur. Therefore, sufficient frictional resistance can be obtained, and stable polishing can be performed at a high polishing rate. Furthermore, since the cleaning liquid is supplied from the back surface of the polishing cloth to the front surface through the through holes of the rotary drum, the polishing debris clogging the polishing cloth is washed away and the cleaning is effectively performed. Therefore, the life of the polishing cloth is extended.

[Brief description of drawings]

FIG. 1 is a schematic perspective view illustrating an implementation situation of a method of the present invention using a polishing tool and a substrate holder.

FIG. 2 is a schematic side sectional view of the polishing tool shown in FIG.

3 is a schematic side cross-sectional view showing the main parts of the polishing tool and the substrate holder shown in FIG.

FIG. 4 is a perspective view illustrating a conventional method for polishing a semiconductor substrate.

[Explanation of symbols]

 Reference Signs List 10 polishing device 12 polishing tool 14 substrate holder 16 suction plate support 18 circular recess 20 suction plate 22 rotary shaft 24 through hole 26 rotary drum 28 holding arm 30 rotary shaft 32 supply port 34 inside rotary drum 36 hose 38 polishing cloth 40 Through hole

Claims (2)

[Claims] 1. A cylinder in which a semiconductor substrate is held on a substrate holder with its surface exposed, and the polishing cloth having fine through holes is wrapped around the substrate while rotating the substrate about an axis orthogonal to the substrate. While pressing and contacting the rotating drum surface with the rotating substrate surface, it is moved forward and backward to rotate, while introducing a polishing liquid or a cleaning liquid into the rotating drum,
A method for polishing a semiconductor substrate, characterized in that polishing and cleaning of the semiconductor substrate are performed while supplying a polishing liquid or a cleaning liquid to the substrate surface through the fine through holes provided in the wall of the rotating drum and the fine through holes of the polishing cloth. . 2. A substrate holder that holds a semiconductor substrate such that the surface is exposed and rotates the substrate about an axis orthogonal to the substrate, and a surface of the substrate on the rotating substrate holder that is rotated is polished. A combination with a polishing tool, wherein the substrate holding table includes a substrate suction plate that holds the substrate by vacuum suction, and a rotating mechanism that rotates the substrate suction plate around an axis orthogonal to the substrate. , A cylindrical rotating drum that is rotatable about a rotation axis along the longitudinal centerline, a holding arm that supports the rotation shaft at both ends, and a rotating drum that is in pressure contact with the substrate surface via the holding arm. And a reciprocating mechanism that rotates while advancing and retreating to, a fine through hole is provided in the cylindrical wall of the rotating drum,
Further, a water-permeable polishing cloth for polishing the substrate surface is attached to the outer peripheral surface of the cylindrical wall, and the rotating shaft of the rotating drum is
A polishing apparatus comprising: a supply port for supplying a polishing liquid or a cleaning liquid from the outside; and a means for introducing the polishing liquid or the cleaning liquid into the rotary drum from the supply port.